Methylene Blue Removal from Aqueous Solution by Adsorption on Archidendron jiringa Seed Shells

A study of batch and column adsorption using A. jiringa seed shell as a natural adsorbent to remove methylene blue from aqueous solution was carried out. This study aimed to determine the effectiveness of A. jiringa seed shell in removing methylene blue as well as to determine the isotherm and adsorption kinetics of methylene blue by A. jiringa seed shells. Parameters in the batch study showed optimum pH for adsorption was at pH 7 with the optimum contact time of 60 minutes whereas the adsorbent dose obtained was 12 g/l. The percentage removal of methylene blue increased with elevated temperature while the ionic strength reduced the adsorption capacity in the dye uptake. Langmuir isotherm was suitable for this study rather than Freundlich model due to the higher regression value: R2 = 0.9999. The most suitable kinetic model for this study was the pseudo second order, compared to pseudo first order, Elovich and intra particle with the value of regression: R2 = 0.9158. This column adsorption study used several different flow rates: 15 mL/min, 18 mL/min, 21 mL/min, 24 mL/min and 27 mL/min for 75 minutes long. The breakthrough time was lesser: 10 minutes in higher flow rates (24 mL/min and 27 mL/min), which indicated the shorter time for the adsorbent to be saturated. Thomas and Yoon & Nelson’s models were proven to be more suitable compared to Bohart-Adams model for the fixed bed adsorption study.

Optimization Conditions of the Preparation of Activated Carbon Based Egusi (<i>Cucumeropsis mannii</i>Naudin) Seed Shells for Nitrate Ions Removal from Wastewater

Egusi seed shells (ESS) were used as precursor for the preparation of two activated carbons (ACs) following H3PO4 and ZnCl2 activation. The effect of factors controlling the preparation of ACs such as chemical activating agent concentration (2 - 10 M), activation temperature (400°C - 700°C) and residence time (30 - 120 min) were optimized using the Box-Behnken Design (BBD). The optimized activated carbons based H3PO4 (ACP) and ZnCl2 (ACZ) were characterized by N2 adsorption, elemental analysis, atomic force microscopy (AFM), Boehm titration and Fourier transformed infrared (FTIR) techniques. The specific surface area was found to be 1053.91 and 1009.89 m2·g-1 for ACP and ACZ respectively. The adsorbents had similar surface functionalities and were both microporous. The effect of various parameters such as initial pH, concentration, and contact time on the adsorption of nitrate ions on ACP and ACZ in aqueous solution was studied. ACZ demonstrated better adsorption capacity (8.26 mg·g-1) compared to ACP (5.65 mg·g-1) at the same equilibrium time of 20 min. The adsorption process was governed by a “physical interactions” phenomenon for both adsorbents.

Adsorptive Treatment of Textile Wastewater Using Activated Carbon Produced from Mucuna pruriens Seed Shells

Mucuna pruriens seed shells (abundantly available agricultural waste) were processed, treated and activated using 60% orthophosphoric acid for removal of congo red and malachite green from an aqueous solution. Its physicochemical properties and its removal efficiencies on the textile dyes were determined. The effect of particle size, adsorbent dose, initial pH of solution, adsorbate concentration and contact time on the process of adsorption was investigated. The equilibrium, kinetic and thermodynamic properties of the dyes removal were also investigated. The experi-mental data were modeled using linear regression method of analysis. The correlation coefficient was used as a criterion for model adequacy and acceptance. Sum of squares error was used to val-idate the isotherm models. The pseudo second-order kinetic model was found to best correlate the experimental data. The intraparticle diffusion is not the only rate controlling step in the process. The experimental data were found to follow the Langmuir, Freundlich and Tempkin isotherm models. The negative free energy indicated that the adsorption processes were spontaneously feasible. The process of adsorption has been found to be endothermic in nature. The removal of malachite green was found to be more spontaneous and feasible than the removal of congo red on the adsorbent. From the study it was deduced that the Mucuna pruriens seed shells activated with phosphoric acid were found to be a good adsorbent for the treatment of textile wastewater con-taining congo red and malachite green.

Photochemical synthesis of bimetallic Au-Ag nanoparticles with “core-shell” type structure by seed mediated catalytic growth

The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4∶1 to 1∶4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4∶1 to 1∶1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1∶4 molar ratio, having a striking feature of forming (interconnected) network structure.

Improving the electrocatalytic activity of Fe,N co-doped biochar for polysulfide by regulation of N-C and Fe-N-C electronic configurations

The conversion of agricultural residual biomass into biochar as a sulfur host material for Li-S batteries is a promising approach to alleviate the greenhouse effect and realize waste resource reutilization.However,the large-scale application of pristine biochar is hindered by its low electrical conductivity and limited electrocatalytic sites.This paper addressed these challenges via the construction of Fe-N co-doped biochar(Fe-NOPC)through the copyrolysis of sesame seeds shell and ferric sodium ethylenediaminetetraacetic acid(NaFeEDTA).During the synthesis process,NaFeEDTA was used as an extra carbon resource to regulate the chemical environment of N doping,which resulted in the production of high contents of graphitic,pyridinic,and pyrrolic N and Fe-Nx bonds.When the resulting Fe-NOPC was used as a sulfur host,the pyridinic and pyrrolic N would adjust the surface electron structure of biochar to accelerate the electron/ion transport,and the electropositive graphitic N could be combined with sulfur-related species via electrostatic attraction.Fe-Nx could also promote the redox reaction of lithium polysulfides due to the strong Li-N and S-Fe bonds.Benefiting from these advantages,the resultant Fe-NOPC/S cathode with a sulfur loading of 3.8 mg·cm^(-2)delivered an areal capacity of 4.45 mAh·cm^(-2)at 0.1C and retained a capacity of 3.45 mAh·cm^(-2)at 1C.Thus,this cathode material holds enormous potential for achieving energy-dense Li-S batteries.

S-8大孔树脂-C18柱联用分离牡丹籽壳中短叶松素及抗氧化研究

以牡丹籽壳为原料,利用大孔树脂和C18反相键合硅胶柱(C18柱)联合分离短叶松素,回收率为(98.33±0.64)%。用70%(体积分数)乙醇提取牡丹籽壳粗黄酮(Mu Dan Ke Flavonoids,MDKF),得率最高为(10.54±0.13)%;比较了6种大孔树脂(AB-8、S-8、DM301、HPD600、HPD100和D101)的吸附率和解析率,发现S-8大孔树脂的吸附率和解析率最佳,分别为83.47%和84.46%;优化S-8大孔树脂分离MDKF的最佳条件为:上样液质量浓度1.6 mg/mL,上样液流速2.0 mL/min,洗脱剂乙醇体积分数60%,洗脱液流速1.5 mL/min,洗脱液体积100 mL;对经过C18柱分离后的组分进行LC-MS分析得到短叶松素,回收率为(98.33±0.64)%;分离前后抗氧化能力比较:C18纯化物>S-8大孔树脂纯化物>MDKF粗提物;分子对接实验表明,短叶松素与超氧化物歧化酶、过氧化氢酶、过氧化物酶、谷胱甘肽过氧化物酶均有结合能力,过氧化氢酶的结合能力最强为-9.1 kcal/mol。实验表明,短叶松素具有较好的抗氧化能力,可作为食品、药品或化妆品等抗氧化剂的添加,应用前景非常广泛,对牡丹籽壳的进一步开发利用提供理论支持。

基于超声改性橡胶籽壳活性炭的制备方法研究

以农业废弃物橡胶籽壳为原料,以KOH为活化剂,与超声处理相结合制备活性炭,通过调整制备处理条件对活性炭的表面结构进行调控,以获得最佳制备条件。采用傅里叶显微红外、扫描电镜、元素分析、热重分析等手段,研究活性炭的物理化学特性,考察其吸附能力,并比较超声预处理与未超声预处理的活性炭的特性。研究得出最优制备条件为:剂料比为1∶1,超声作用时间为60 min,活化时间为60 min,活化温度为700℃。超声预处理后的活性炭(UAC)的亚甲基蓝吸附值为400 mg/g、碘吸附值为1340.2 mg/g、得率达25.9%,总孔容为0.9511 cm^(3)/g,比表面积为1034.5009 m^(2)/g;未经超声预处理的活性炭(NAC)的亚甲基蓝吸附值为300 mg/g,碘吸附值为894.0 mg/g,得率为20.8%,比表面积为690.2461 m^(2)/g,总孔容为0.6830 cm^(3)/g。二者均含羟基、醇羟基、羰基官能团,橡胶籽壳活性炭的氮气吸附等温线为Ⅰ型。KOH活化后的活性炭表面存有大量孔结构,UAC活性炭表面光滑平整,有许多丰富规则的孔结构,优于NAC活性炭。橡胶籽壳的碳(C)含量丰富,经过KOH活化后,UAC和NAC的C含量由原来的56.81%,分别提高到75.97%、64.89%。KOH活化后的样品比橡胶籽壳更加稳定,UAC和NAC样品的总重量分别损失62%和68%之后趋于稳定。综上所述,超声处理制备的活性炭性能更佳,说明超声波的空化效应作用在活性炭结构表面,使其结构发生变化,进而提高其吸附性能、比表面积等。

紫苏籽壳提取物纳米银颗粒的制备及性能表征

为进一步提高紫苏资源的利用价值,本研究以紫苏籽壳提取物(PSHE)为原料,通过单因素实验,分别考察硝酸银浓度、提取液浓度、超声波功率、超声温度和超声时间对紫苏籽壳提取物纳米银(PSHE@AgNPs)银离子还原率的影响,并在单因素实验基础上,采用响应面法对超声波辅助制备PSHE@AgNPs的工艺进行优化,并采用X射线衍射、傅里叶变换红外光谱、热重分析及透射电子显微镜对PSHE@AgNPs的结构及性能进行表征。结果表明,PSHE@AgNPs制备最佳工艺为:硝酸银浓度15 mmol/L,提取液浓度0.4 g/mL,超声波功率480 W,超声温度80℃,超声时间7 h,在此工艺条件下制备的PSHE@AgNPs银离子还原率达92.37%。X射线衍射分析表明PSHE@AgNPs具有面心立方结构;傅里叶变换红外光谱表明PSHE@AgNPs表面存在植物化学物质,酚类化合物参与纳米银的合成;热重分析显示了PSHE@AgNPs的热稳定性,在276.7~420.3℃范围内存在主要的质量损失,质量减少46.74%;透射电子显微镜显示PSHE@AgNPs是粒径均值为27.97 nm的近球形分散颗粒。研究结果可为超声波辅助绿色合成粒径小、分散性高、具有热稳定性的面心立方结构的PSHE@AgNPs提供理论指导,并推动其在生物材料和医学领域的应用。

Au/Ag核-壳结构复合纳米粒子形成机制的研究

在已制备好的Au纳米粒子表面 ,通过化学还原的方法沉积生长Ag包覆层 .通过控制Au ,Ag的比例 ,制备了粒度均匀且粒径可控的Au/Ag核 -壳结构纳米粒子 .利用UV vis吸收光谱和透射电子显微镜 (TEM)对Au,Ag摩尔比为 1∶10的复合纳米粒子的光学性质和形态进行随时监测 ,直接观察了核 -壳结构纳米粒子的生长过程 :一部分Ag+ 在Au核表面还原生长 ,溶液中其余Ag+ 还原形成银的纳米团簇向粒子表面的继续沉积生长 。

交联核壳结构PBA/PS和PBA/PMMA纳米微球的制备与应用

考察了聚丙烯酸丁酯/聚苯乙烯(PBA/PS)以及聚丙烯酸丁酯/聚甲基丙烯酸甲酯(PBA/PMMA)交联核壳结构纳米高分子微球的制备方法,并对其在尼龙复合材料中的应用进行了初步研究.结果表明,通过交联剂的引入使粒子核层和壳层内部均形成了高度交联的结构,可以限制亲水性较小的聚苯乙烯(PS)壳层向粒子内部迁移的趋势;制备出的微球平均粒径为40～50 nm,粒径分布很窄.采用饥饿态加料方式加入第二单体不仅可以使微球具有较高的产率和凝胶率,而且可以使其具有更理想的核壳结构和更窄的粒径分布.此外,将合成出的PBA/PMMA核壳粒子对尼龙6基体进行复合的结果表明,由于该微球表面与尼龙6基体之间具有较强的界面相互作用且微球具有较大的形变能力,可以在基体中形成良好的分散,在保持材料强度的同时有效地提高了其刚性和韧性.

10t/d双螺杆榨油机压榨油茶籽的工艺研究

为提高油茶籽油的品质,减少传统油茶籽制油工艺对油茶籽油的营养成分损失,对日处理10t双螺杆榨油机压榨油茶籽的工艺进行了研究。结果表明,最佳工艺条件为:油茶籽经过分级处理后入榨油茶仁水分控制在9%、油茶仁中含壳控制在8%时,压榨饼中残油率为2.49%,且产品符合一级油的国家标准。与市场上销售的油茶籽油相比,通过本工艺获得的油茶籽油中α-生育酚的保留率更高,从而进一步提高油茶籽油的营养价值,可为我国油茶籽油的高值化加工提供了技术参考。

芡实壳提取物的抗氧化活性及对口腔溃疡模型大鼠的治疗作用

目的研究芡实壳对口腔溃疡模型大鼠的防治作用及其潜在作用机制。方法分别以福林酚法、硝酸铝比色法测定芡实壳-萃取物中多酚、黄酮含量;以DPPH·、ABTS^(+)·、·OH和·O_(2)4种自由基清除实验评价体外抗氧化活性;冰醋酸灼伤法建立口腔溃疡大鼠模型。采用酶联免疫法检测血清中氧化因子水平;HE染色观察溃疡黏膜组织病理变化;Western blot方法检测溃疡黏膜组织中Keap1、Nrf2、Nes-Nrf2和HO-1蛋白表达水平。结果乙酸乙酯萃取物中多酚、黄酮含量为306.74±1.04 mg/g、23.43±0.61 mg/g,其清除DPPH·、ABTS^(+)·自由基的IC50分别是3.42±0.97µg/mL、3.32±0.90µg/mL(P<0.01);乙酸乙酯组能明显改善模型动物口腔黏膜损伤,提高血清中CAT水平、降低MDA水平(P<0.01),显著增加血清中NEs-Nrf2(P<0.01)以及HO-1(P<0.05)蛋白表达量、降低Keap1(P<0.01)蛋白表达量显著。结论芡实壳提取物对口腔溃疡有一定治疗作用,其作用机制可能是通过激活Keap1/Nrf2/HO-1信号通路。

PS/MA-TiO_2复合纳米微球作为润滑油添加剂的研究

采用原位种子乳液聚合法合成了 PS/ MA- Ti O2 核壳结构复合纳米微球 ,并通过透射电镜 (TEM)、红外 (IR)、差热 (DSC)、失重 (TGA)和 XPS等测试对其结构、性能和摩擦表面的组成进行了分析。在四球试验机上考察了其摩擦学行为 ,结果表明 ,PS/ MA- Ti O2 核壳结构复合纳米微球用作润滑油添加剂有良好的抗磨性 ,并能显著提高基础油的失效负荷 。

不同处理对轮台白杏种子发芽及幼苗生长的影响

【目的】掌握轮台白杏种子的最佳育苗方法,为高效科学育苗提供技术支撑,为揭示杏休眠机理提供理论依据。【方法】以轮台白杏种子为研究对象,设置激素法、温汤浸种法、低温层积法、激素+低温层积法打破种子休眠,统计发芽率,将萌发的种子播种到土壤中,30 d后测定幼苗特性。【结果】1)GA_(3)和温汤浸种处理不去皮种子,发芽率很低,表明轮台白杏具有种皮休眠特性。带壳轮台白杏种子经低温层积80 d才开始萌发,说明轮台白杏具有种壳休眠特性。2)在不同处理中,有两个处理方法发芽率及出苗率均较高,其中500 mg/L的GA_(3)处理半去皮轮台白杏种子,发芽率高达94.00%,出苗率高达88.00%,种苗根系发达,不易徒长,育苗成本最低,每千株为276元,育苗效率最高。温汤浸种轮台白杏种子在50℃浸种全去皮轮台白杏种子30 min,发芽率和出苗率均较高,分别为98.00%和84.00%,成本较低,效率较高。低温层积带壳种子120 d时发芽率最高为80.67%,所有低温层积处理出苗率低于70%,育苗成本较高,效率最低。3)先用激素浸泡种24 h,后层积综合处理发现,轮台白杏种子发芽率及出苗率均不高,且成本最高,育苗效率不高。【结论】杏具有种皮、种壳休眠特性。500 mg/L的GA_(3)浸泡半去皮种子24 h与50℃浸种全去皮轮台白杏种子30 min,育种成本较低,效率较高,均可用作生产中的育苗方法。

AAS核壳结构共聚物的制备及其改性SAN树脂的性能

随着社会对环保问题的关注,乳液聚合用于脆性聚合物的改性研究越来越受到重视。文中采用种子乳液聚合方法制备了核壳结构聚丙烯酸丁酯/苯乙烯-丙烯腈共聚物(PBA/AS,简称AAS),单体总转化率达99.35%,乳胶粒理论粒径与实测值基本一致,说明该体系没有明显的二次成核过程。当乳胶粒粒径在326 nm、橡胶质量分数为15%时,AAS改性苯乙烯-丙烯腈共聚物的共混体系发生明显的脆-韧转变,而拉伸强度保持较高的值。DMA谱图表明,随橡胶相含量的增大,两相转变峰越来越接近,相容性提高;SEM观察证实了这种力学性能的转变。

种子乳液聚合制备可发气P(St/BVA)-PSt核壳微球

在种子乳液聚合中加入发泡剂偶氮二甲酰胺(AC),制备可发气P(St/BVA)-PSt核壳微球,并与单纯种子乳液聚合进行了对比,探讨了种子乳液聚合制备核壳结构聚合物粒子的形成机理,分析了可发气微球的形态、结构及热分解特性。结果表明,单纯种子乳液聚合过程生成了新的乳胶粒,包覆AC种子乳液聚合过程未生成新的乳胶粒;前者的反应速率比后者的大;发泡剂AC在180℃加热4～5min出现突发性分解,平衡发气量为175mL/g,可发气微球中的AC分解平缓,平衡发气量为128mL/g。

PBA-aPS核壳乳胶粒子的制备及其性能表征

采用预乳化半连续种子乳液聚合方法制备了聚丙烯酸丁酯-无规立构聚苯乙烯(PBA-aPS)核壳乳胶粒子,讨论了单体纯化、引发剂加入方式以及聚合反应条件对苯乙烯(St)转化率的影响,并设计正交实验得到最佳合成工艺,并对核壳乳胶粒子进行了表征。结果表明:核壳乳胶粒子以轻度交联的PBA为核、aPS为壳,核壳结构明显;乳胶粒子呈圆球状,平均尺寸约340nm,分布比较均一,粒子粘连情况通过降温出料得以解决;核壳粒子具有较高的热稳定性,分解温度高达324℃,加工过程中粒子没有发生形变;粒子的堆砌并不影响粒子在间同立构聚苯乙烯(sPS)基体中分散,说明PBA-aPS核壳粒子填充改性sPS是完全可行的。

P(BA-EHA)/PVC复合胶乳的制备及表征

采用乳液聚合法合成了丙烯酸丁酯与丙烯酸 2 乙基己酯交联共聚物 [P(BA EHA) ]乳液 ,以P(BA EHA)乳液为种子通过与氯乙烯 (VC)聚合制备了P(BA EHA) PVC复合胶乳 .考察了P(BA EHA)乳液用量对复合胶乳粒径及其材料力学性能的影响 ,借助透射电镜 (TEM)、扫描电镜 (SEM)和动态力学分析 (DMA)等手段对复合胶乳粒子及其所制材料的形态结构进行了表征 .DMA研究结果表明 ,橡胶相P(BA EHA)与基体PVC间相容性得到了良好改善 .随着P(BA EHA)含量的增加 ,低温区材料的力学损耗峰较纯聚氯乙烯增强 ,且峰位逐渐向高温区移动 .TEM照片显示 ,复合胶乳粒子具有清晰的核壳结构 ;P(BA EHA)非常均匀地分散在PVC中 ,两相界面模糊 .由SEM照片可见 ,材料缺口断面表现为很好的韧性断裂 .含 4 2 %P(BA EHA)材料的缺口抗冲强度是PVC的 11倍 ,断裂伸长率较PVC提高近两倍 .

含壳率对油茶籽油品质特性的影响

为了探究螺旋压榨过程中含壳率对油茶籽油品质特性的影响规律,考察了含壳率对螺旋压榨油茶籽油的出油率、理化指标、生物活性物质、脂肪酸组成、氧化诱导时间以及挥发性风味成分等品质特性的影响。结果表明,螺旋压榨出油率随着含壳率的增加而提高,到20%时趋于稳定,最高出油率为26.29%。且当壳质量分数为20%时,油茶籽油的酸价、过氧化值、水分及挥发物质量分数均最低,分别为0.82 mg/g、0.37 mmol/kg和0.07%,氧化诱导时间最长,为22.62 h,同时其色度值和磷脂含量均处较低水平。当壳质量分数为30%~40%时,油茶籽油中多酚含量最高,为67.48 mg/kg,且油茶籽油的色泽相对较深。含壳率对油茶籽油的甾醇、角鲨烯、维生素E含量以及脂肪酸组成无显著影响。通过电子鼻和GC-IMS对不同含壳率油茶籽油中挥发性风味成分进行分析,结果表明,油茶籽油中主要挥发性化合物为醛类、醇类、酯类、酮类和杂环类物质等,且含壳率较高的油茶籽油和含壳率较低的油茶籽油中的挥发性成分有显著差异,当壳质量分数低于20%时,油茶籽油中挥发性成分含量较多,其香味较为浓郁,随着含壳率的增加,油茶籽油中挥发性物质含量也随之减少。综合油茶籽油的理化指标、生物活性物质含量、氧化稳定性及挥发性成分含量,螺旋压榨油茶籽油时的物料理想壳质量分数为20%。

AC对St或MMA为壳层单体种子乳液聚合的影响

在种子乳液聚合中加入发泡剂偶氮二甲酰胺(AC),制备了可发气核壳结构复合微球。探讨了AC用量对以聚苯乙烯(PSt)微凝胶为种子,St或甲基丙烯酸甲酯(MMA)为壳层单体的2种体系稳定性及转化率和反应速率的影响。结果表明,以MMA为壳层单体的聚合体系是较理想体系。当AC用量从1g增加到8g时,以St为壳层单体体系的最终转化率从96.2%下降到74.2%,以MMA为壳层单体体系的最终转化率基本不变,保持在96%左右。但AC的加入使以MMA为壳层单体体系的反应速度最大值的出现时间推后了10min,且其值仅为未加入AC体系的1/2左右。